After pressing exit game, the game does NOT shut down.

I click save game [from years worth of crash experiences], and then I click save and exit. The screen will eventually freeze(like it does when starting exit sequence), but not ever ever ever shut down. I clicked save and exit once and immediately went downstairs. I came back up three hours later and the game was frozen, but still on. I can not use task manager to force close game as it just leaves me with a blank white screen. I have to manually force PC off.